We finished installing a new belt driven 70 amp Plane Power alternator on the
IO-470 in the Deb today. It comes with a new mounting bracket, new stabilizing
arm and belt tightening bracket. Everything fit perfectly. The Plane Power 70
amp alternator weighs 10 pounds, the same as the 50 amp InterAv alternator it
replaced, but it has a state of the art small voltage regulator that replaced
the InterAv's voltage regulator, over voltage relay and huge capacitor. The
Plane Power kit also comes with an "ALT INOP" 100 milliamp warning
light that must be mounted on the panel in the sight of the pilot and connected
to a power source through a one amp fuse or breaker on one side, and to a
terminal on the voltage regulator on the other.
We fired up the engine to test it and put about a 45 amp load on it, and at
950 RPM it held 14.1 volts. The staff at Plane Power told me this alternator
will deliver 70 amps at cruise RPM. Note not all 12 volt Plane Power alternators
are 70 amps, the gear driven alternator that fits on the E series engines is 50
amps, and they also have some 60 amp models. If you have a belt driven
alternator or still have the belt driven generator, this is a good option to
upgrade to current technology, and I like the warning light that will illuminate
if the alternator goes off line. Another Beech Boy recently installed the gear
driven Plane Power alternator on the E series engine in his E35, replacing his
old 35 amp generator, and is very happy with it, also.
Picture of the installation attached, when the picture was taken we were not
finished tie wrapping the wires, etc. The Plane Power alternator is physically
smaller than the InterAv alternator it replaced, but weighs as much, 10 pounds,
versus 17 pounds for the old 50 amp generator we removed about 7 years ago. We
replaced the InterAv alternator because it failed, bad bearings probably
resulted in physical damage to two of the three field/armature components or the
brushes/commutator, it would only produce about 15 amps and upon removal the
bearings were obviously worn out, the shaft had about 1/4 inch of end play.
We also replaced the drive pulley on the engine, the old one was a little
dented. That job was a little tricky, using a puller to get the old one off and
driving the new one on far enough to get enough threads on the shaft to move it
the rest of the way on with the nut. Not much clearance back there, but far more
clearance than Cessnas have!